Rating plates are permanent labels attached to various products to convey the product's serial number, the name and/or trademark of the manufacturer, date of manufacture, UL approval (UL is a trademark of Underwriters Laboratories, Inc.), and other similar information. Since the information on these plates must be readable for the life of the product, and sometimes beyond, the apparatus used for generating these plates must be designed to print plates that are easy to read and that cannot be erased by ordinary means.
Until recently, such plates were generally printed exclusively by professional printers in print shops. Due to the relatively high cost of setting up printing plates and the associated tooling, compared with the cost of printing each additional label, the cost per plate of printing rating plates this way is quite high unless a large quantity of labels (e.g., at least 10,000) is printed. The present invention virtually eliminates the cost of setting up a plate or label and thereby substantially reduces the cost of printing small quantities of rating plates and similar labels.
With the growing use of microcomputers and personal computers, there have been a number of programs written for printing labels using these machines. Generally, these programs have printed only text on labels, such as a set of addresses stored in a data base.
Other products, such as the MacIntosh computer made by Apple Computer include work processing programs that can combine text and graphics. While the documents created by such a product could be printed on labels, these products do not have a number of features which are important for a versatile label maker:
(1) efficiently using a high resolution printer for printing text and graphics side by side,
(2) means for printing a series of different label designs on each row of labels,
(3) means printing several different labels in an interleaved pattern, and for updating a different serial number for each one,
(4) means for printing bar codes, and
(5) a high resolution impact printer for making permanent and easy to read labels.
The term "text" is used herein to mean alphanumeric characters represented by a sandard text code, such as ASCII code. The term "graphics", on the other hand, is used herein to mean images which are represented by either an array of pixels, a set of vectors, or any equivalent means for representing images. Therefore, if an alphanumeric character is represented by an array of pixels instead of a text code, it is considered herein to be a graphic image rather than text.
While the term "label" is broader than the term "rating plate" (rating plates are permanent, high resolution labels), for most purposes the terms "plate", "rating plate" and "label" are herein used interchangeably.
All of the above identified features are important. First, the use of graphics is important because rating plates tend to be small, and therefore the manufacturer of the product is often identified by use of a trademark instead of the manufacturer's corporate name. Similarly, many product labels carry house marks indicating that the products have passed a well known set of quality standards.
Second, a number of the present invention's features are related to the need to use a high resolution impact printer. In the preferred embodiment, the printer is a Toshiba model 321, which is a 24 pin dot matrix impact printer with a resolution of 180 pixels per inch.
The need to accommodate conventional label designs and the small size of most rating plates make it important to be able to print both graphics and text side by side. At the same time, it is important to be able to print labels reasonably quickly. The problem here is that impact printers are generally much slower when printing graphics than when printing text. Therefore converting the entire label into a grapics image is not an acceptable solution, because it would make printing too slow. On the other hand, switching back and forth between graphics and text printing modes presents a number of other problems which are described, along with their solution, below.
Another feature, the ability to interleave the printing of different label designs, is important because many products need more than one rating plate or label. The present invention allows this feature to be fully exploited by providing a plurality of different print ordering patterns, and by allowing the different label designs being printed on the same line of blank labels to use the same and/or different graphics at the same or different vertical printing positions.
Still another feature of the present invention is the ability to put boxes around any selected portion of a label. Boxes are often used to highlight serial numbers, and sometimes other information which the user may need to provide when requesting help from the product's manufacturer.
Finally, the present invention provides the ability to automatically generate standardized bar codes in combination with text and graphics on a single rating plate or label. This combination of features allows the design and printing of plates with virtually the same flexibility as one would have using a print shop.
It is therefore a primary object of the present invention to provide an improved label printing apparatus and method that permits the design and printing of rating plates and other labels with a varity of features including the printing of text and high resolution graphics side by side, and interleaved printing of different labels.